Electrode with wing-shaped brackes for cathode ray tubes



Nov. 24, 1970 J. H. JOHNSON ELECTRODE WITH WING-SHAPED BRACKETS FORCATHODE RAY TUBES Filed Oct. 14, 1968 INVENTOR JAY H. JOHNSON ATTORNEYUnited States Patent US. Cl. 31382 8 Claims ABSTRACT OF THE DISCLOSURE Acylindrical electrode is provided for cathode ray tube electron gunswith two normally disposed bracket members adapted to enter a mountingbead and which extend from a rolled over edge of cylindrical tubing bentback to form a coaxial skirt about the cylindrical electrode body.

This invention relates to cathode ray tube electrodes and moreparticularly to color tube cylindrical electrodes having bracketsaffixed thereto.

In the development of electron gun assemblies for color picture tubeshaving three separate electron gun assemblies it has been customary toretain electrodes of three separate guns in fixed position by holdingthe electrodes in three separate glass beads by means of mounting strapswelded onto the cylindrical electrode structures. A single strap curvedabout each electrode and welded thereto similar in principle to that ofthe US. Pat. No. 2,909,689 has been employed with extending end clampsoriented to permit side by side electrodes to be mounted into a singleglass bead. However, such construction requires critical shaping of thestrap to conform exactly with the outer cylindrical curvature of thecylindrical electrode. Since the straps are formed and tempered in largequantities and metal has elastic properties not always retaining itsshaped form, and because such straps are exposed both in tempering andin use to high heats that tend to warp or twist the metal it has beenalmost impossible to conform the shape of the strap exactly with that ofthe cylindrical electrode. In consequence, when spot welding techniquesare used, a strap that is forced into place and held by three or morespot welds tends to fail when put under thermal and mechanical stresses.The choice of more than one Welding point about the circumference of thecylindrical surface requires almost perfect fit to prevent some sort ofstress during the spot welding operation. Gaps of spacing of brackets,weld splashes in mounting them and distorted electrode cylinder surfacescontribute to corona and arcing in high voltage CRT electrodes. Yet inthe prior art for color guns it has been customary to employ thesecontoured strap configurations, because they have been less susceptibleto failure through welding puddles and splashes than pin type bracketsor those butt welded onto an electrode cylinder.

Other electron gun structures for cathode ray tubes combining severalbeams within a single electrode and also plate like substantially planarelectrodes are known. In these electrodes there is a similar problem ofmounting firmly and exactly in an immovable position by extending abracket into a glass mounting bead. Not always are these structuresadaptable to the use of straplike brackets. Thus a single techniqueuseful for improved mounting in a variety of electrode configurations isnot generally available in the prior art.

Another factor desirable in multiple beam guns is to provide a mountingconfiguration which prevents arcing between electrodes in the variousguns. It has been ice difficult with some configurations to separate thebrackets from each other by any significant distance, and large closeparallel surfaces can introduce enough capacitance to providelimitations in electrical performance.

Any bracket configuration provided must be firm and affixed to theelectrode in such a manner to hold the electrode in precise positionwithout movement in the presence of significant thermal and physicalstresses, such as that permitted by weld failures and surface flexing.

Accordingly it is a general object of this invention to provide a newarticle of manufacture comprising a cathode ray electrode of novelconfiguration solving the foregoing problems of the prior art.

A more specific object of the invention is to provide suitable mountingbrackets for color television electrodes which are integrally formed toextend from exterior surface of the cylindrical electrodes.

A further object of the invention is to produce mouning brackets forcolor television electrodes of integral construction in such form tomake them less critical in construction and at the same time improvingtheir functional performance and strength by holding the electrodes inthe mounting bead in two dimensions.

Another object of the invention is to provide mounting brackets formultiple beam electron gun electrodes affording less reaction betweenelectrodes in the separate guns.

Still another object of the invention is to provide universal typemounting brackets useful on a variety of different electrodeconfigurations.

In particular it is an object of this invention to produce mountingbrackets for high voltage cathode ray electrodes which reducepossibilities of failure through arcing, corona or electrical leakage.

Thus, in accordance with the invention, a cylindrical electrodestructure is provided with integral mounting tabs in the form of atleast two wing members extending from and integral with the electrodestructure. They may extend from a rolled over skirt portion disposedcoaxially alongside a narrow portion at one end of the cylindricalelectrode tubing to form a claw member for protruding into a glassmounting head. The claw member is shaped to enter the glass bead in twonormal planar sheets, one of which extends a significant distance alongthe axial length of the electrode, and is preferably disposed to mountthe electrode substantially symmetrically about the center of gravity ofthe electrode. The bracket is so located on the circumference of theelectrode to extend outwardly generally radially toward one edge of thebead and shaply deviates at an angle into the bead to thereby spaceadjacent portions of bracket members from different electrodes enteringthe same bead at greater distances than conventional with prior artstrap structures.

The foregoing objectives together with further features and advantagesof the invention are set forth hereinafter by reference to theembodiment of the invention shown in the accompanying drawing, wherein:

FIG. 1 is an elevation fragmentary view, in section of a CRT gridelectrode structure as positioned in an electron gun with mountingbrackets engaging a glass bead member.

FIG. 2 is a plan view of the electrode structure of FIG. 1, and

FIG. 3 is an elevation view in section of a further CRT grid structureembodying the invention.

As may be seen from the embodiment of FIGS. 1 and 2, a CRT first gridelectrode 5 is formed of a cylindrical tubing 7 with a closed end, cupshaped member 6 having a single beam passageway along axis 8 passingthrough aperture 9. The cylinder is rolled over at end to form a narrowskirt portion 11 outside of and generally coaxial with the cylindertubing 7.

Extending from the skirt portion 11 substantially normally with the axis8 is a first planar member 12 of a mounting bracket bent to form aperpendicular planar claw member 14 extending alongside the electrodegenerally parallel with the axis 8. The claw member has an indentation15 for grasping the glass bead member 16 to hold the electrode in placein a gun assembly (not shown) in a critical position relative to theother adjacent electrodes.

In order to precisely mount and hold a cathode ray tube electrodewithout tilting or moving during any physical stresses caused by fields,beams, heat changes or mechchanical forces encountered after manufactureof the electron gun, the wing-shaped claw member 12-14 is integral withthe electrode and extends beyond the electrode to engage the glass head16 in two substantially normal planes, one of which extends in a planenormal to the beam axis and the other of which is disposed a significantlength parallel to the axis 8 of the cylindrical electrode 5. This givesfirmness and removes the tendency to twist and warp that results when abracket claw is disposed along a single plane.

Furthermore there are no welds, and the narrow skirt portion 11 isstrong and firm to hold the claw members 12-14 in perfect registrationfrom one electrode to the next. In order to alleviate any tendency forthe electrode to move or twist on its axis, the planar claw member 14having indentation 15 is disposed on opposite sides of the plane ofcenter of gravity 20 of the electrode.

The criticality of dimensioning is even more important in the case ofthree gun color picture tubes, since all three guns must register witheach other to form a set of beams commonly swept by a deflection system(not shown). In such guns two planar members are disposed at angles ofsubstantially 120 as indicated by angle x, and adjacent electrodes notedby primed reference numbers are mounted in common glass beads 16 bytheir wing-shaped claw bracket members 12-14 as indicated in FIG. 2.

As may be seen, the planar extension 12 integrally connected to theelectrode extends beyond its confines in a substantially radialdirection at positions such that the general orientation of the planarportion 12 changes its direction to dispose face-to-face the axial endplate members 14 in the region of the bead. This construction keeps thecapacitance between the brackets low and the distancesparticularly inair-between two adjacent brackets remote to improve functionalperformance by reducing feed through discharges due to arcing, etc.

This mounting structure is useful in the various other tubularelectrodes of an electron gun, as for example in the third gridstructure shown in FIG. 3. The use of common reference characters hereidentifies corresponding portions of the electrode structure which issubstantially different in that the cylindrical electrode has its tubingportion formed with two different diameters 26 and 27.

Typical inner diameters of cylindrical electrodes constructed in thisway may range in the order of .250 to .400 inch, and the overall lengthsrange in the order of .220 to 1.000 inch, but other dimensions may alsobe used if desirable. In these ranges the skirt may have a radius of.015 inch and the axial length of the claw member 14 may be in the rangeof .150 to .300 inch.

It is clear that the foregoing construction is novel and providesadvantageous performance in the critical environ- 4 ment encountered inelectron gun assemblies. Therefore those features of novelty believeddescriptive of the spirit and nature of this invention are defined withparticularity in the appended claims, for which Letters Patent arepetitioned.

What is claimed is:

1. An electrode for a cathode ray tube electron gun with a mounting beadholding a series of beam processing electrodes in precisely spacedpositions comprising at least one aperture for passing an electron beamalong an axis and affecting its eletcrical characteristics, at least apair of wing-shaped plate members extending integrally from theelectrode substantially normally with the beam axis, each being formedat one end with a member adapted to grip said electron gun mounting beadand forming an angle with two components normal to each other andextending respectively generally perpendicular to and generally parallelwith the axis of the beam, wherein each said wing-shaped member is sodimensioned and disposed to engage with said two components a mountinghead to support in two substantially normal planes one of which extendsa significant length parallel to the axis of the beam.

2. An electrode as defined in claim 1 having a closed cylindrical cupconfiguration with at least one axial aperture therein.

6. An electrode as defined in claim 2 wherein the cylindrical electrodeis generally formed to have two different diameters along the axialdimension.

4. An electrode as defined in claim 1 wherein the wingshaped platemembers are limited to two with a planar member generally extending atintervals about the electrode.

5. An electrode as defined in claim 4 wherein the two wing-shapedmembers are spaced about the electrode at positions where a portion ofthe plate member near the electrode extends substantially radially fromthe beam axis and its remote end changes direction toward the positionof a glass bead in its mounted position.

6. An electrode as defined in claim 1 wherein a planar claw memberextends alongside said electrode disposed on opposite sides of thecenter of gravity of the electrode and oriented to enter a mounting beadgenerally parallel to said beam axis.

7. An electrode as defined in claim 1 wherein the electrode is agenerally cylindrical tubing with one end thereof rolled over to producea narrow skirt portion outside of and generally coaxial with saidcylindrical tubing, and said plate members extend normally to the beamaxis from the skirt portion to project the component of the plate memberwhich is parallel with the axis of the beam alongside the electrode bodyfor a substantial portion of its length.

8. An electrode as defined in claim 7 wherein the component parallel tothe axis of the beam is disposed to mount the electrode at its center ofgravity.

References Cited UNITED STATES PATENTS 2,909,689 10/1959 Case 3l3-256 X2,942,128 6/1960 Johnson 3 l382 3,239,708 3/1966 Johnson 31'3823,265,920 8/1966 Fiore 3l382 X JAMES W. LAWRENCE, Primary Examiner V.LAERANCHI, Assistant Examiner U.S. Cl. X.R. 313-256, 289, 356

